Melt extraction pathways and stagnation depths beneath the Madeira and Desertas rift zones (NE Atlantic) inferred from barometric studies

Schwarz, Stefanie; Klügel, Andreas; Wohlgemuth‐Ueberwasser, Cora C.

doi:10.1007/s00410-004-0556-4

Cited by 49 publications

(30 citation statements)

References 39 publications

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“…This would be akin to the shallow (upper crustal) version of a "hot zone" (Annen et al 2006). Other volcanoes with multi-stage magma plumbing systems developed large conical edifices through centralized plumbing systems (Hansteen et al 1998;Schwarz et al 2004); however, Oki-Dōzen grew a nest-shaped volcano, possibly due to lower magma volumes and a more dispersed plumbing. Filtering by the multi-stage plumbing may have prevented the thermal destabilization of the shallower reservoir (Ōyama syenite).…”

Section: Significance For Intraplate Alkalic Volcanismmentioning

confidence: 98%

A trachyte–syenite core within a basaltic nest: filtering of primitive injections by a multi-stage magma plumbing system (Oki-Dōzen, south-west Japan)

Brenna

Nakada

Miura

et al. 2015

Contrib Mineral Petrol

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that distinguish it from the rest of the system. Geochemical modelling indicates that magmatic differentiation through crystal fractionation and minor crustal assimilation occurred in crustal and shallow sub-volcanic magma reservoirs. In the central part of the system, a number of vertically spaced reservoirs acted as a filter, capturing basaltic dykes and hindering their ascent. In the outer region, dykes either reached the surface unhindered and erupted to form the basaltic/trachybasaltic succession or stalled at crustal levels and differentiated to trachyte before forming dispersed domes/flows. The central plumbing system "filter" resulted in a nest-shaped volcano, with a trachytic core surrounded by basaltic products, and stopped direct injection of basaltic magmas into the shallow syenitic magma reservoir, likely preventing its destabilization and explosive eruption.

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Section: Significance For Intraplate Alkalic Volcanismmentioning

confidence: 98%

A trachyte–syenite core within a basaltic nest: filtering of primitive injections by a multi-stage magma plumbing system (Oki-Dōzen, south-west Japan)

Brenna

Nakada

Miura

et al. 2015

Contrib Mineral Petrol

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“…This model has proved to be able to recreate P-T conditions for a wide range of magma compositions, within a reasonable margin of error, and has been frequently used in the last decade (e.g. Shaw and Klügel 2002;Putirka and Condit 2003;Schwarz et al 2004;Caprarelli and Riedel 2005;Galipp et al 2006;Mordick and Glazner 2006;Longpré et al 2008;Barker et al 2009). Crucially, it has proved to be applicable to analogue (high P-T) experiments (Putirka 2008) while also correlating well with independent methods for natural samples (Klügel and Klein 2005).…”

Section: Clinopyroxene-melt Thermobarometersmentioning

confidence: 99%

Magma plumbing beneath Anak Krakatau volcano, Indonesia: evidence for multiple magma storage regions

Dahrén

Troll

Andersson

et al. 2011

Contrib Mineral Petrol

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Understanding magma plumbing is essential for predicting the behaviour of explosive volcanoes. We investigate magma plumbing at the highly active Anak Krakatau volcano (Indonesia), situated on the rim of the 1883 Krakatau caldera by employing a suite of thermobarometric models. These include, clinopyroxene-melt thermobarometry, plagioclasemelt thermobarometry, clinopyroxene composition barometry and olivine-melt thermometry. Petrological studies have previously identified shallow magma storage in the region of 2-8 km beneath Krakatau, while existing seismic evidence points towards midto deep-crustal storage zone(s), at 9 and 22 km respectively. Our results show that clinopyroxene in Anak Krakatau lavas crystallized at a depth of 7-12 km, while plagioclase record both shallow crustal (3-7 km) and sub-Moho (23-28 km) levels of crystallisation. These magma storage regions coincide with well constrained major lithological boundaries in the crust, implying that magma ascent and storage at Anak Krakatau is strongly controlled by crustal properties. A tandem seismic tomography survey independently identified a separate upper crustal (< 7 km) and a lower to mid-crustal magma storage region (> 7 km). Both petrological and seismic methods are sensitive in detecting magma bodies in the crust, but suffer from various limitations. Combined geophysical and petrological surveys, in turn, offer increased potential for a comprehensive characterization of magma plumbing at active volcanic complexes.

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“…It is noteworthy that systematic petrographic differences distinguish the EMRP and LMRP rocks (Schwarz et al 2004): (1) highly phyric lava flows such as ankaramites and plagioclase-phyric rocks occur exclusively in EMRP units (with the exception of local ankaramite occurrences on Desembarcadouro Island); (2) phenocrysts >2 mm in size are far more abundant in EMRP rocks than in LMRP rocks; and (3) olivine in EMRP rocks is commonly associated with titaniferous augite, whereas LMRP rocks mostly contain olivine as the only phenocryst phase.…”

Section: Age Inmentioning

confidence: 98%

“…1). Alternatively, Madeira and the Desertas Islands may represent two discrete volcanoes that coalesced during their volcanic evolution and growth (Schwarz et al 2004.…”

Section: Geological Settingmentioning

confidence: 99%

“…The Desertas Islands, investigated and described in detail by , and Schwarz et al (2004Schwarz et al ( , 2005, represent the well exposed shallow core of a fossil rift zone and may serve as a type example for rift structures of many oceanic island volcanoes. Ponta de São Lourenço at the easternmost tip of Madeira also shows excellent three-dimensional exposures of rift structures, but except for two rock ages from near the peninsula (Mata et al 1995) and thermobarometric data (Schwarz et al 2004), no geochemical data or age determinations from this locality have been published so far. In a detailed field study of eastern Madeira including Ponta de São Lourenço, Ramalho (2004) and Ramalho et al (2005) focused on tectonic and geomorphological aspects and produced a geological map more detailed than a previous general map by Zbyszewski et al (1975).…”

Section: Introductionmentioning

confidence: 99%

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Structure and evolution of the volcanic rift zone at Ponta de São Lourenço, eastern Madeira

et al. 2008

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Ponta de São Lourenço is the deeply eroded eastern end of Madeira's east-west trending rift zone, located near the geometric intersection of the Madeira rift axis with that of the Desertas Islands to the southeast. It dominantly consists of basaltic pyroclastic deposits from Strombolian and phreatomagmatic eruptions, lava flows, and a dike swarm. Main differences compared to highly productive rift zones such as in Hawai'i are a lower dike intensity (50-60 dikes/km) and the lack of a shallow magma reservoir or summit caldera. 40 Ar/ 39 Ar age determinations show that volcanic activity at Ponta de São Lourenço lasted from >5.2 to 4 Ma (early Madeira rift phase) and from 2.4 to 0.9 Ma (late Madeira rift phase), with a hiatus dividing the stratigraphy into lower and upper units. Toward the east, the distribution of eruptive centers becomes diffuse, and the rift axis bends to parallel the Desertas ridge. The bending may have resulted from mutual gravitational influence of the Madeira and Desertas volcanic edifices. We propose that Ponta de São Lourenço represents a type example for the interior of a fading rift arm on oceanic volcanoes, with modern analogues being the terminations of the rift zones at La Palma and El Hierro (Canary Islands). There is no evidence for Ponta de São Lourenço representing a former central volcano that interconnected and fed the Madeira and Desertas rifts. Our results suggest a subdivision of volcanic rift zones into (1) a highly productive endmember characterized by a central volcano with a shallow magma chamber feeding one or more rift arms, and (2) a less productive endmember characterized by rifts fed from deep-seated magma reservoirs rather than from a central volcano, as is the case for Ponta de São Lourenço.

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Melt extraction pathways and stagnation depths beneath the Madeira and Desertas rift zones (NE Atlantic) inferred from barometric studies

Cited by 49 publications

References 39 publications

A trachyte–syenite core within a basaltic nest: filtering of primitive injections by a multi-stage magma plumbing system (Oki-Dōzen, south-west Japan)

A trachyte–syenite core within a basaltic nest: filtering of primitive injections by a multi-stage magma plumbing system (Oki-Dōzen, south-west Japan)

Magma plumbing beneath Anak Krakatau volcano, Indonesia: evidence for multiple magma storage regions

Structure and evolution of the volcanic rift zone at Ponta de São Lourenço, eastern Madeira

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